(1) Field of Invention
Conventional evaporative cooler operates by using directly outside air. As the result in high temperature the useful air will not be cold enough and because of high temperature of the useful air and its content of moisture the occupant of an enclosure will not experience great degree of comfort. Also as the useful air should be discharged from the enclosure because of the high pressure of the air and this air discharging from the enclosure is colder as compared with outside air, so energy is wasted. But even now from the point of less energy cost in comparison with some other cooling devices and also because of possibility to produce it in big and small size and making the air fresh and clean, the evaporative cooler is the most useful device. For this reason removing deficiency of evaporative cooler is a very important matter.
(2) Description of the Prior Art
For the purpose of removing the deficiency of the evaporative cooler a variety of designs have been proposed wherein the heat absorptive action of evaporative is employed to reduce the temperature of a heat exchanger apparatus and the fresh air is then passed through the heat exchanger apparatus for purpose to be cold. The air which is used to effect evaporation (working air) is conducted to the atmosphere and the useful air is directed into the room. In this way effort is made to remove the deficiency of the evaporative cooler. In these designs wasting of energy is high and useful air is not fresh and with water vapor and enough coldness. At 5/11/72 the design No. 10584 was proposed and patented by the inventor of the present invention wherein a portion of the useful air was employed to reduce the temperature of a heat exchanger apparatus and the inlet fresh air by passing through the said heat exchanger was precold before to be employed as working air for evaporation and as the result the cooler produced useful air colder and with less water vapor in comparison with ordinary evaporative cooler. Although this invention was useful, because of low efficiency of the heat exchanger and using a portion of the useful air, the waste of energy was high to some extent. Then other designs have been proposed wherein the indoor air which was precold by passing through a heat exchanger was employed as working air for evaporation. So the working air (the indoor air) was precold before being employed for evaporation and this precold indoor air after again being cooled inside the device by evaporation was used to reduce the temperature of the heat exchanger in which the outdoor air passed for being cooled and entering the room. The heat exchanger which is used in these design is made by laminating of corrugated plates between flat plate to have two air flows crossing orthogonally. These heat exchanger has nothing in their canals to help the exchange of the heat and corrugate plates which cause the air passing through the canals only in one side has enough contact with the adjacent wall. This heat exchanger which is used inside the air condition has limit heat exchanging surface and makes the entire system big and as the air employing for evaporation exhaust near the ports in which the inlet fresh air is sucked, it needs dehumidifying system and as the result the air of the enclosure would not be pleasant. These designs not being simple as evaporative cooler nevertheless change the nature of evaporative cooler because in these designs outdoor fresh air is not employed as working air to produce useful air fresh, cold clean with water vapor as is true with evaporative cooler. So none of these designs could replace evaporative cooler completly, the reason being that although above mentioned designs have some privileges they do not hold special privileges of the evaporative cooler like simplicity and less cost of energy and inexpensive and also making the air cold clean with water vapor which is desirable in the dry climate. In these designs the working air which leaves the device to atmosphere is colder than the outside temperature so a lot of energy is wasted. The evaporative cooler is a useful device; its problem is that when the weather is too hot the water vapor of the useful air is high and the useful air is not cold enough. Another important deficiency of the evaporative cooler is that when as the result of the high air pressure the useful air leaves the room it takes coldness generated by the evaporative cooler to outside, so the energy is wasted.
The present invention satisfies the foregoing deficiency of the evaporative cooler without having much energy cost and even in some instances without further energy cost.